/*
* Udp.cpp: Library to send/receive UDP packets with the Arduino ethernet shield.
* This version only offers minimal wrapping of socket.c/socket.h
* Drop Udp.h/.cpp into the Ethernet library directory at hardware/libraries/Ethernet/
*
* NOTE: UDP is fast, but has some important limitations (thanks to Warren Gray for mentioning these)
* 1) UDP does not guarantee the order in which assembled UDP packets are received. This
* might not happen often in practice, but in larger network topologies, a UDP
* packet can be received out of sequence.
* 2) UDP does not guard against lost packets - so packets *can* disappear without the sender being
* aware of it. Again, this may not be a concern in practice on small local networks.
* For more information, see http://www.cafeaulait.org/course/week12/35.html
*
* MIT License:
* Copyright (c) 2008 Bjoern Hartmann
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* bjoern@cs.stanford.edu 12/30/2008
*/
#ifndef udp_h
#define udp_h
#define UDP_TX_PACKET_MAX_SIZE 24
class UdpClass {
private:
uint8_t _sock; // socket ID for Wiz5100
uint16_t _port; // local port to listen on
uint16_t _offset; // offset into the packet being sent (used in streaming API)
public:
UdpClass() : _sock(MAX_SOCK_NUM) {};
uint8_t begin(uint16_t); // initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
int available(); // has data been received?
// C-style buffer-oriented functions
uint16_t sendPacket(uint8_t *, uint16_t, uint8_t *, uint16_t); //send a packet to specified peer
uint16_t sendPacket(const char[], uint8_t *, uint16_t); //send a string as a packet to specified peer
int readPacket(uint8_t *, uint16_t); // read a received packet
int readPacket(uint8_t *, uint16_t, uint8_t *, uint16_t *); // read a received packet, also return sender's ip and port
// readPacket that fills a character string buffer
int readPacket(char *, uint16_t, uint8_t *, uint16_t &);
// Finish with the UDP socket
void stop();
// API to let you build up a packet in a number of steps. Useful for when
// you need to send a large packet but don't have enough memory to hold it
// all in place at one time
// Start building a packet to send to the specified peer
// @param ip - destination IP address
// @param port - destination port number
// @return 1 if successful, or 0 if there was an error
uint16_t startSendPacket(uint8_t *ip, uint16_t port);
// Add data to the packet about to be sent. Only valid to call this after
// a call to startSendPacket and before finishSendPacket
// @param buf - data to append to the outgoing packet
// @param len - number of bytes to append from buf
// @return Number of bytes successfully appended
uint16_t addData(uint8_t *buf, uint16_t len);
// Send the packet. Only valid to call this after a call to startSendPacket
// and at least one call to addData
// @return 1 if successful, or 0 if there was an error
uint16_t finishSendPacket(); //send the packet
// Streaming API for reading packets. Can't be mixed and matched with
// the readPacket calls. Useful for processing large incoming packets
// where you don't have enough space to read it in one go
// Start reading in a packet of data
// @param ip Buffer to hold the IP address of the server that sent the packet
// @param port The remote port that the packet came from
// @return Number of bytes of data in the packet or -1 if there was an error
int startReadPacket(uint8_t *ip, uint16_t &port);
// Read a bufLen bytes of data from the packet. Only valid after a call to
// startReadPacket.
// @param buf Buffer to hold the data read in
// @param bufLen Number of bytes to read
// @return Number of bytes successfully read
int readPacketData(uint8_t *buf, uint16_t bufLen);
// Read a single byte from the packet. Only valid after a call to
// startReadPacket.
// @return Byte read from the packet
uint8_t readPacketByte();
// Test whether or not all of the data for the packet has been read. Only
// valid after a call to startReadPacket.
// @return Returns true if the end of the packet has been reached, or false
// if there is still data left to be read
int readPacketReachedEnd();
// Finish reading in the packet. This should be called when you have finished
// with the contents of this packet. Only valid after calls to
// startReadPacket, readPacketData and readPacketByte
void finishReadPacket();
};
#endif